Door movement indicators which make a sound or noise to indicate the opening or closing, or movement of a door have been known and used in the art. It has been common to use bells or buzzers in public shops to indicate the presence of a customer and in homes to indicate the entrance and departure of guests or children. Devices using musical tones such as bells or even stringed devices have also been used. Stringed door movement indicators have taken the form of the strings being strung over a hollow resonant box similar to that used in a stringed instrument such as a guitar or a violin which has an opening or openings in the front thereof, and chime balls or clappers are suspended over the strings as in the patent to Garson U.S. Pat. No. 2,705,936. One of the disadvantages of the above described musical door movement indicators is that, while they can provide high quality tonal resonance, even a cursory inspection reveals a device which involves a considerable number of steps in the fabrication thereof to construct the resonance box. Further, the opening tends to be unsightly and subject to dust accumulation, etc.
In view of the above, it can be seen that there is a need for a device which achieves relatively high quality tonal resonance and can be manufactured simply and efficiently and inexpensively. The disclosed invention provides just such a device having a unique and revolutionary resonance producing feature to provide reduced construction costs.